﻿684 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  immediate 
  contact 
  with 
  the 
  soluble 
  sulfates. 
  While 
  only 
  a 
  small 
  

   quantity 
  of 
  barium 
  salt 
  is 
  required, 
  still 
  to 
  insure 
  thorough 
  mixing, 
  

   10 
  to 
  20 
  times 
  the 
  necessary 
  amount 
  should 
  be 
  employed, 
  and 
  it 
  

   can 
  be 
  used 
  without 
  any 
  injurious 
  results. 
  The 
  following 
  example 
  

   is 
  given 
  by 
  Gerlach. 
  The 
  clay 
  must 
  first 
  be 
  (thoroughly 
  analyzed 
  

   to 
  determine 
  the 
  amount 
  of 
  sulfates. 
  If, 
  for 
  example, 
  the 
  clay 
  con- 
  

   tained 
  .1^ 
  of 
  sulfate 
  of 
  lime, 
  this 
  would 
  mean 
  that 
  one 
  pound 
  con- 
  

   tained 
  .4 
  of 
  a 
  gram, 
  and 
  theoretically 
  every 
  gram 
  of 
  sulfate 
  of 
  

   lime 
  needs 
  1.45 
  grams 
  of 
  barium 
  carbonate 
  to 
  render 
  it 
  insoluble; 
  

   therefore 
  theoretically 
  a 
  pound 
  of 
  clay 
  would 
  require 
  .6 
  of 
  a 
  gram 
  

   of 
  barium 
  carbonate, 
  or 
  for 
  safety 
  six 
  or 
  seven 
  grams 
  should 
  be 
  

   used 
  for 
  every 
  pound 
  of 
  clay. 
  This 
  would 
  be 
  about 
  one 
  hundred 
  

   pounds 
  for 
  every 
  thousand 
  bricks, 
  based 
  on 
  the 
  supposition 
  that 
  a 
  

   gTeen 
  brick 
  weighs 
  seven 
  pounds. 
  As 
  a 
  pound 
  of 
  barium 
  carbonate 
  

   costs 
  2^c, 
  the 
  amount 
  of 
  it 
  required 
  for 
  a 
  thousand 
  brick 
  would 
  cost 
  

   $2.50. 
  It 
  is 
  cheaper 
  to 
  use 
  barium 
  chlorid 
  for 
  the 
  reason 
  that 
  the 
  

   salt 
  is 
  soluble 
  in 
  water, 
  and 
  hence 
  can 
  be 
  distributed 
  more 
  evenly, 
  

   with 
  the 
  use 
  of 
  a 
  smaller 
  quantity. 
  The 
  chemical 
  reaction 
  takes 
  

   place 
  much 
  more 
  quickly 
  when 
  the 
  barium 
  chlorid 
  is 
  used. 
  There 
  

   is 
  the 
  objection 
  to 
  it 
  that 
  as 
  near 
  as 
  possible 
  the 
  theoretic 
  amount 
  

   must 
  be 
  used, 
  for, 
  if 
  any 
  of 
  it 
  remains 
  in 
  the 
  clay, 
  without 
  reacting 
  

   with 
  any 
  sulfate, 
  it 
  will 
  form 
  an 
  incrustation 
  on 
  the 
  surface 
  of 
  the 
  

   brick. 
  To 
  give 
  an 
  example 
  of 
  the 
  use 
  of 
  chlorid 
  of 
  barium, 
  we 
  may 
  

   take 
  again 
  a 
  clay 
  containing 
  .1^ 
  of 
  calcium 
  sulfate. 
  This 
  would 
  

   require 
  theoretically 
  1.8 
  grams 
  of 
  crystallized 
  barium 
  chlorid 
  and, 
  

   passing 
  over 
  the 
  intermediate 
  stages 
  of 
  the 
  calculation, 
  a 
  thousand 
  

   bricks 
  would 
  require 
  57.4 
  kilograms 
  of 
  barium 
  chlorid. 
  If 
  barium 
  

   cost 
  2Jc 
  a 
  pound, 
  a 
  thousand 
  brick 
  would 
  require 
  an 
  extra 
  outlay 
  

   of 
  only 
  32c, 
  in 
  using 
  barium 
  chlorid. 
  Chlorid 
  of 
  lime 
  is 
  also 
  

   formed, 
  but 
  this 
  has 
  no 
  injurious 
  effect 
  provided 
  the 
  clay 
  is 
  heated 
  

   to 
  such 
  a 
  temperature 
  as 
  will 
  cause 
  the 
  lime 
  to 
  unite 
  with 
  other 
  

   bases 
  and 
  silica, 
  and 
  form 
  a 
  complex 
  silicate. 
  If 
  heated 
  high 
  

   enough 
  to 
  decompose 
  the 
  chlorid 
  of 
  lime, 
  it 
  might 
  be 
  that 
  its 
  sub- 
  

   sequent 
  slaking 
  would 
  be 
  injurious. 
  

  

  